// 
// Copyright (c) 2006-2009 Ben Motmans
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// Author(s):
//    Ben Motmans <ben.motmans@gmail.com>
//

using System;
using System.Collections.Generic;

namespace Anculus.Core
{
	/// <summary>
	/// <see cref="IInserter"/> implementation to insert an item at a random position in an array or list.
	/// </summary>
	public sealed class RandomInserter : AbstractInserter
	{
		private Random random;
		
		public RandomInserter ()
		{
			random = new Random (DateTime.Now.Millisecond);
		}
		
		public override int Insert<T> (List<T> list, IComparer<T> comparer, T item)
		{
			if (list == null)
				throw new ArgumentNullException ("list");
			if (comparer == null)
				throw new ArgumentNullException ("comparer");

			int rand = random.Next (0, list.Count);
			if (list.Count == 0 || rand == list.Count) {
				list.Add (item);
				return rand;
			} else {
				list.Insert (rand, item);
				return rand;
			}
		}

		public override int Insert<T> (ref T[] array, IComparer<T> comparer, T item)
		{
			if (array == null)
				throw new ArgumentNullException ("array");
			if (comparer == null)
				throw new ArgumentNullException ("comparer");

			int index = random.Next (0, array.Length);
			Insert<T> (ref array, index, item);
			return index;
		}
	}
}
